Elevated partial pressure of carbon dioxide is mostly higher than 50 mmHg, mostly seen in type II respiratory failure, and can be accompanied by partial pressure of oxygen lower than 60 mmHg, most commonly in the acute exacerbation of COPD. If the elevation is mild, the patient can be given continuous low-flow oxygen and naloxone to promote breathing and expel excess carbon dioxide. If the partial pressure of carbon dioxide does not decrease and does not improve after using the above methods, and the patient becomes drowsy and mentally ill, it is necessary to apply non-invasive ventilator assisted breathing or tracheal intubation and invasive ventilator assisted breathing, depending on the situation.